CR: (Take 4) Remove polling inside UNIX audio thread

Description
----------------------------------
The audio out class for UNIX is creating a thread that
continuously 
attempts to read from the list of available audio data
buffers, and
then use the device specific method for writting that data
to the audio
device.

This change will introduce a new IHXEvent for letting the
main thread
signal the data writing thread when new data is available
for pushing to
the audio device, instead of having the audio thread do a
bunch of small
micro sleeps while it waits for some new data to push.

If data is available for writting to the device, then a
small sleep is
still added for none ALSA based device, since none ALSA
devices will not
block on write (making it possible for the thread to spin
until the
audio device is ready to accept new data.)

By doing this we remove a source of interrupts that tend to
drive
the CPU into high C0 (full power mode) residency.  This is
especially
true when on a MID device that has the ASound prealloc
buffer max'ed
out, allowing large periods of time for the original output
audio thread
to wait for new blocks of data.

Files Modified
----------------------------------
audio/device/platform/unix/audUnix.cpp
audio/device/pub/platform/unix/audUnix.h

Branches
---------------------------------
HEAD, hxclient_3_1_0_atlas

Index: platform/unix/audUnix.cpp
============================================================
=======
RCS file: /cvsroot/audio/device/platform/unix/audUnix.cpp,v
retrieving revision 1.12
diff -u -r1.12 audUnix.cpp
--- platform/unix/audUnix.cpp	6 Jul 2007 20:21:16
-0000	1.12
+++ platform/unix/audUnix.cpp	28 Apr 2008 20:07:39 -0000
 -73,7
+73,8 
 #include "hxprefs.h"
 #endif 

-
+#include "hxtlogutil.h"
+#include "ihxtlogsystem.h"

 //-1 is usually considered to be no file descriptor.
 const int CAudioOutUNIX::NO_FILE_DESCRIPTOR = -1;
 -102,6
+103,7 
     m_audioThread(NULL),
     m_bUserWantsThreads(TRUE),
     m_ulSleepTime(0),
+    m_pAvailableDataEvent(NULL),
 #endif
     m_pRollbackBuffer(NULL)
 {
 -114,7
+116,6 
     //Allco our write buffer list. Want to throw from here?
You will,
like
     //it or not.
     m_pWriteList = new CHXSimpleList();
-    
 }

 void CAudioOutUNIX::_initAfterContext()
 -142,6
+143,7 
 	CreateInstanceCCF(CLSID_IHXMutex,
(void**)&m_mtxWriteListPlayStateLock, m_pContext);
 	CreateInstanceCCF(CLSID_IHXMutex,
(void**)&m_mtxDeviceStateLock,
m_pContext);
 	CreateInstanceCCF(CLSID_IHXThread,
(void**)&m_audioThread,
m_pContext);
+	CreateInstanceCCF(CLSID_IHXEvent,
(void**)&m_pAvailableDataEvent,
m_pContext);
     }
 #endif    

 -194,6
+196,7 
         HX_RELEASE( m_mtxWriteListPlayStateLock );
         HX_RELEASE( m_mtxDeviceStateLock );
         HX_RELEASE( m_audioThread );
+        HX_RELEASE( m_pAvailableDataEvent );
     }
 #endif    

 -353,6
+356,8 
     //Wait for it to do so and clean up.
     if( m_bUserWantsThreads )
     {
+        HXLOGL4 (HXLOG_ADEV,
"CAudioUnixOUT::_Imp_Close signaling
event..."); 
+        m_pAvailableDataEvent->SignalEvent();
         m_audioThread->Exit(0);
     }

 -778,8
+783,21 
         that->m_mtxDeviceStateLock->Unlock();
         that->m_mtxWriteListPlayStateLock->Unlock();

-        //OK, sleep the amount of time it takes to play 1/4
of the
device's buffer.
-        microsleep(that->m_ulSleepTime/4); 
+        if(bReadyToExit == FALSE) 
+	{
+	    if (that->m_pWriteList->GetCount() == 0 ||
that->m_wState ==
RA_AOS_OPEN_PAUSED)
+	    {
+	        HXLOGL4 (HXLOG_ADEV,
"CAudioUnixOUT::AudioThread() waiting for
audio data..."); 
+	        that->m_pAvailableDataEvent->Wait(ALLFS);
+            } 
+            else
+	    {
+#if !defined(HELIX_FEATURE_ALSA)
+	        // OK, sleep the amount of time it takes to play
1/4 of the
device's buffer.
+	        microsleep(that->m_ulSleepTime/4); 
+#endif
+	    }
+	}
     }

     //Signal the parent thread that we are done.
 -833,6
+851,7 
     }

     UNLOCK(m_mtxWriteListPlayStateLock);
+    HXLOGL4 (HXLOG_ADEV, "CAudioUnixOUT::_PushBits()
writing %i bits",
(int)ulBufLen);
     _WriteBytes(pData, ulBufLen, lCount);
     LOCK(m_mtxWriteListPlayStateLock);

 -995,6
+1014,8 
     //grab the data and write it to the device.
     if( m_bUserWantsThreads )
     {
+        HXLOGL4 (HXLOG_ADEV,
"CAudioUnixOUT::_Imp_Write signaling
event..."); 
+        m_pAvailableDataEvent->SignalEvent();
         return RA_AOE_NOERR;
     }
 #endif    
Index: pub/platform/unix/audUnix.h
============================================================
=======
RCS file:
/cvsroot/audio/device/pub/platform/unix/audUnix.h,v
retrieving revision 1.8
diff -u -r1.8 audUnix.h
--- pub/platform/unix/audUnix.h	6 Jul 2007 20:21:19
-0000	1.8
+++ pub/platform/unix/audUnix.h	28 Apr 2008 20:07:39 -0000
 -289,6
+289,7 
     IHXThread*	m_audioThread;
     HXBOOL      m_bUserWantsThreads;
     ULONG32	m_ulSleepTime;
+    IHXEvent*	m_pAvailableDataEvent;
 #endif    

   private:

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CR: (Take 4) Remove polling inside UNIX audio thread

Thread: CR: (Take 4) Remove polling inside UNIX audio thread